Fitness Correlates Of Song Repertoire Size In Free-Living Song Sparrows (Melospiza Melodia)

Models of sexual selection propose that exaggerated secondary sexual ornaments indicate a male\u27s own fitness and the fitness of his offspring. These hypotheses have rarely been thoroughly tested in free-living individuals because overall fitness, as opposed to fitness components, is difficult to measure. We used 20 years of data from song sparrows ( Melospiza melodia) inhabiting Mandarte Island, British Columbia, Canada, to test whether a male\u27s song repertoire size, a secondary sexual trait, predicted overall measures of male or offspring fitness. Males with larger song repertoires contributed more independent and recruited offspring, and independent and recruited grandoffspring, to Mandarte\u27s population. This was because these males lived longer and reared a greater proportion of hatched chicks to independence from parental care, not because females mated to males with larger repertoires laid or hatched more eggs. Furthermore, independent offspring of males with larger repertoires were more likely to recruit and then to leave more grandoffspring than were offspring of males with small repertoires. Although we cannot distinguish whether observed fitness variation reflected genetic or environmental effects on males or their offspring, these data suggest that female song sparrows would gain immediate and intergenerational fitness benefits by pairing with males with large song repertoires

Conceptual learning : the priority for higher education

The common sense notion of learning as the all-pervasive acquisition of new behaviour and knowledge, made vivid by experience, is an incomplete characterisation, because it assumes that the learning of behaviour and the learning of knowledge are indistinguishable, and that acquisition constitutes learning without reference to transfer. A psychological level of analysis is used to argue that conceptual learning should have priority in higher education

Effects of season and reproductive state on lipid intake and fatty acid composition of gastrointestinal tract contents in the European hare

We investigated lipid content and fatty acid (FA) composition of gastrointestinal tract contents in free-living, herbivorous European hares (Lepus europaeus). Mean crude fat content in hare stomachs and total gastrointestinal (GI) tracts was higher than expected for typical herbivore forages and peaked in late fall when hares massively deposited body fat reserves. Changes of FA proportions in different parts of the GI-tract indicated a highly preferential absorption of polyunsaturated fatty acids (PUFA). A further reduction of PUFA content in the caecum, along with the appearance of odd-chained FAs in caecum, caecotrophes, and colon content, pointed to a biohydrogenation of PUFA in the hare’s hindgut. GI-tract contents showed significant seasonal changes in their FA composition. Among PUFA, α-linolenic acid peaked in spring while linoleic acid was predominant in late summer and fall, which probably reflected changes in the plant composition of forage. However, independent of seasonal changes, GI-tracts of lactating females showed a significantly (+33%) higher content of linoleic acid, a FA that is known to increase reproductive performance in European hares. This finding suggests that lactating females actively selected dietary plants rich in linoleic acid, a PUFA that may represent a limited resource for European hares

Revisiting Reflection: Utilizing Third Spaces in Teacher Education

Much has been written about the importance of reflective practice. What is missing is reflective work on the part of teacher educators to address the mismatch between university-based methods courses and the realities of classroom life. With examples from a third grade mathematics classroom as well as a university-based mathematics methods course, this article explores ways educators can employ third space theory as a way to engage in purposeful reflection into their teaching practices

Risk factors for sickness absence due to low back pain and prognostic factors for return to work in a cohort of shipyard workers

The purpose of this study was to determine risk factors for the occurrence of sickness absence due to low back pain (LBP) and to evaluate prognostic factors for return to work. A longitudinal study with 1-year follow-up was conducted among 853 shipyard workers. The cohort was drawn around January 2004 among employees in the shipyard industry. Baseline information was obtained by questionnaire on physical and psychosocial work load, need for recovery, perceived general health, musculoskeletal complaints, sickness absence, and health care use during the past year. During the 1-year follow-up for each subject medical certifications were retrieved for information on the frequency and duration of spells of sickness absence and associated diagnoses. Cox regression analyses were conducted on occurrence and on duration of sickness absence with hazard ratios (HR) with 95% confidence interval (95% CI) as measure of association. During the 1-year follow-up period, 14% of the population was on sick leave at least once with LBP while recurrence reached 41%. The main risk factors for sickness absence were previous absence due to a health problem other than LBP (HR 3.07; 95%CI 1.66–5.68) or previous sickness absence due to LBP (HR 6.52; 95%CI 3.16–13.46). Care seeking for LBP and lower educational level also hold significant influences (HR 2.41; 95%CI 1.45–4.01 and HR 2.46; 95%CI 1.19–5.07, respectively). Living with others, night shift and supervising duties were associated with less absenteeism due to LBP. Workers with a history of herniated disc had a significantly decreased rate of returning to work, whereas those who suffered from hand-wrist complaints and LBP returned to work faster. Prior sick leave due to LBP partly captured the effects of work-related physical and psychosocial factors on occurrence of sick leave. Our study showed that individual and job characteristics (living alone, night shift, lower education, sick leave, or care seeking during the last 12 months) influenced the decision to take sick leave due to LBP. An increased awareness of those frequently on sick leave and additional management after return to work may have a beneficial effect on the sickness absence pattern

Dificultades para codificar, relacionar y categorizar problemas verbales algebraicos: dos estudios con estudiantes de secundaria y profesores en formación

En resolución de problemas verbales por transferencia, la activación de problemas ya conocidos que sirvan de guía, depende de las analogías percibidas entre éstos y el problema a resolver. Se desarrollan dos estudios relacionados para analizar en qué características se basan los estudiantes para codificar problemas y detectar sus analogías, en tareas de categorización (sorting). Se utilizaron técnicas cuantitativas y cualitativas combinadas. Primero se analizó cómo los estudiantes de secundaria son influidos por diferentes variables características de problemas de ciencias. Una gran proporción de sujetos no fue capaz de percibir las analogías y diferencias adecuadas entre problemas. El segundo estudio trató de avanzar una explicación de estos resultados. El nivel académico y la familiaridad con las temáticas fueron factores significativos, pero los futuros profesores participantes mostraron demasiadas dificultades, alertando sobre la conveniencia de revisar algunos supuestos instruccionales habituales

Transcription profiling of lung adenocarcinomas of c-myc-transgenic mice: Identification of the c-myc regulatory gene network

<p>Abstract</p> <p>Background</p> <p>The transcriptional regulator c-Myc is the most frequently deregulated oncogene in human tumors. Targeted overexpression of this gene in mice results in distinct types of lung adenocarcinomas. By using microarray technology, alterations in the expression of genes were captured based on a female transgenic mouse model in which, indeed, c-Myc overexpression in alveolar epithelium results in the development of bronchiolo-alveolar carcinoma (BAC) and papillary adenocarcinoma (PLAC). In this study, we analyzed exclusively the promoters of induced genes by different in silico methods in order to elucidate the c-Myc transcriptional regulatory network.</p> <p>Results</p> <p>We analyzed the promoters of 361 transcriptionally induced genes with respect to c-Myc binding sites and found 110 putative binding sites in 94 promoters. Furthermore, we analyzed the flanking sequences (+/- 100 bp) around the 110 c-Myc binding sites and found Ap2, Zf5, Zic3, and E2f binding sites to be overrepresented in these regions. Then, we analyzed the promoters of 361 induced genes with respect to binding sites of other transcription factors (TFs) which were upregulated by c-Myc overexpression. We identified at least one binding site of at least one of these TFs in 220 promoters, thus elucidating a potential transcription factor network. The analysis correlated well with the significant overexpression of the TFs Atf2, Foxf1a, Smad4, Sox4, Sp3 and Stat5a. Finally, we analyzed promoters of regulated genes which where apparently not regulated by c-Myc or other c-Myc targeted TFs and identified overrepresented Oct1, Mzf1, Ppargamma, Plzf, Ets, and HmgIY binding sites when compared against control promoter background.</p> <p>Conclusion</p> <p>Our in silico data suggest a model of a transcriptional regulatory network in which different TFs act in concert upon c-Myc overexpression. We determined molecular rules for transcriptional regulation to explain, in part, the carcinogenic effect seen in mice overexpressing the c-Myc oncogene.</p